1YRL

Escherichia coli ketol-acid reductoisomerase

1YRL の概要

• エントリーDOI: 10.2210/pdb1yrl/pdb
• 分子名称: Ketol-acid reductoisomerase, SULFATE ION (3 entities in total)
• 機能のキーワード: branched-chain amino acid biosynthesis, knotted protein, reductoisomerase, oxidoreductase
• 由来する生物種: Escherichia coli
• 細胞内の位置: Cytoplasm : P05793
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 217384.00

構造登録者

Tyagi, R.,Duquerroy, S.,Navaza, J.,Guddat, L.W.,Duggleby, R.G. (登録日: 2005-02-04, 公開日: 2005-10-11, 最終更新日: 2023-10-25)

主引用文献

Tyagi, R.,Duquerroy, S.,Navaza, J.,Guddat, L.W.,Duggleby, R.G.
The crystal structure of a bacterial class II ketol-acid reductoisomerase: domain conservation and evolution
Protein Sci., 14:3089-3100, 2005

PubMed Abstract: Ketol-acid reductoisomerase (KARI; EC 1.1.1.86) catalyzes two steps in the biosynthesis of branched-chain amino acids. Amino acid sequence comparisons across species reveal that there are two types of this enzyme: a short form (Class I) found in fungi and most bacteria, and a long form (Class II) typical of plants. Crystal structures of each have been reported previously. However, some bacteria such as Escherichia coli possess a long form, where the amino acid sequence differs appreciably from that found in plants. Here, we report the crystal structure of the E. coli enzyme at 2.6 A resolution, the first three-dimensional structure of any bacterial Class II KARI. The enzyme consists of two domains, one with mixed alpha/beta structure, which is similar to that found in other pyridine nucleotide-dependent dehydrogenases. The second domain is mainly alpha-helical and shows strong evidence of internal duplication. Comparison of the active sites between KARI of E. coli, Pseudomonas aeruginosa, and spinach shows that most residues occupy conserved positions in the active site. E. coli KARI was crystallized as a tetramer, the likely biologically active unit. This contrasts with P. aeruginosa KARI, which forms a dodecamer, and spinach KARI, a dimer. In the E. coli KARI tetramer, a novel subunit-to-subunit interacting surface is formed by a symmetrical pair of bulbous protrusions.

PubMed: 16322583
DOI: 10.1110/ps.051791305

実験手法

X-RAY DIFFRACTION (2.6 Å)